Dyeing of wool with indigo dyestuffs



Patented Oct. 5, 1948 'DYEING OF'WOOL WITH INDIGO 'DYESTUFFS Edward-Weber,.-VVinchester, Mass, assignorto Allied Chemical 8;- DyeCorporation, New York, 'N...,,a.c0rporation of New York NoDrawing;Application March 30, 1944, Serial'No. 528,772

Claims.

This inventionrelates't'o the dyeing of: animal fibers.- and especiallywool, withindigoid vatidyestuil:s-..v Itrelates more. particularly to,an: improved method. of. exhausting an: ammoniahydrosulfite vat of an.indigoid vat-.dyestufi; or related: dye-liquor, employed in' the:dyeing of animalfi-bers.

The dyeing of animal fibers withzindigo-id'vat dyestuffs, and=especiallyindigo, presentsa number-of: difiicultie which ordinarily, are not en'-countered in the; dyeing of cotton and other-vegetable fibers.Thus,,.beoause of the. chemical nature of the animal fibers, itis-necessar-y; to avoid theme of strongly alkaline-vatsorrelated dyeliquors. ticetodyewoolen stock, yarn, slubbing. or piece-- goods in aweakly alkaline vat;. or with a circulating-liquor, containing aleuco-compound of an indigoid vat dyestui'l, aqueous odiurnhydrosulfiteand. aweak. alkali (such as ammonium hydroxide, sodium. carbonate, orthe like): and preferably also containing a dispersion assistant (suchasa-protective colloid or anorganic dispersing agent; for example, glue;gelatin, syn-- thetic organic compounds of the. alkyl aryl sulfonatetype,.and the like) Priorito' thepresent invention, in thedyeing. ofanimalfibers with indigoid vat d'yestufis, it. wasknown to exhaust. anammonia-hydrosulfite vat ofan' indigoid vat dyestuff, or related dyeliquor; by' adding. thereto ammonium sulfate or other acidic substance;such. as. an. acid. (e. g.,.

avneutral salt, whereas for'the. dyeing of animal fiber it wasconsidered: necessary, priort'o' the present invention, to"neutralizethei vat by. means ofan acidic substance in'order' to exhaustit..

(See, for example, American Dyestufii Reporter, vol. XIX-A930, page241.)

. It. has been discovered in accordance with' thev presentinventionrthati. the neutral; alkali metal sulfates and the alkali metalchlorides not only are: efiective as exhausting agents for ammoniahydrosulfit'e-vats in the-dyeing of animal fibers It has accordinglybeen the-.prac

2. with indigoid vat dyestuffs, but in some cases produce superiordyeings. For example, in the dyeing of woolen piece-goods with indigofrom an ammonia-hydrosulfite-glue vat; it has been found, inaccordancewiththe. present invention, if sodium sulfate (e.- g.,Glaubers salt) is added to the vat as an exhausting agent, the resultingdyeings' are about 10% stronger than 'dyeings obtained under-similarc0nditions-with the same materials but with ammonium sulfate as theexhausting agent, and thesdyeings are otherwise substantially identical.

Thus, in accordance with the present. invention, dyeings whichraraofsqualor greater tinctorial strength, as compared with those obtainedwith the use of. ammoniumsulfate, can be. ob-

I tained without sacrificing any of the important qualities of thedyeings' (especially uniformity, penetration, andfastness to" crocking)by the use of'such' readily; available and cheap salts as sodium sulfateand sodium chloride. (It. will'be understood that where sodium sulfateisreferrcd to hereirrand' in the claims, the neutral; sulfate, NazSO4,with or withoutwater of crystallization, isintendedfi' The neutralalkali rnetal sulfate or alkali.- metal "chloride (for example; sodiumsulfate, potassium sulfate, sodium "chloride, potassium chloride;lithium chloride, 'etc;) 'is' preferably addedto the 'vat' or other dyeliquor in small amounts during the course of thetdyeing, to effect agradual precipitation of" the leuco cornpound and thereby promote evendyeings characterized by good penetration and fastness .to' crocking. Iti preferably"'added' to the' dye. liquor: after dyeing has progressed toa substantial degree, inaccordance with the usual pram tioe in theart inexhausting indigoid" vat'dyestuff liquors; it maybe added earlier,however,.

if desired.-

The invention will be illustrated bythe following specific-example, butit isto'beunderstood that the invention is'not limitedto the"cletailsthereof an'dthat' changes maybe made without departing from thescope; of" theinven tion.

EXAMPLE Elevenounce woolen ,piecagoods were processed and dyed .in ropeform inTan ordinary piece-dye kettle (which machine) open. toQthe;

atmosphere in. the following..manner, .theratiO of the goods to thedyebath or liquor beingal- Ways maintained at about 1:20. Eire amount 3Washing The goods were first washed by circulating them for 30 minutesin a bath at 180 F. and

composed of water, 2 lbs. of Nacconol NP. (9. commercial surface-activeagent comprising a mixture of alkyl benzene sodium sulfonate derivedfrom kerosene) and 4 lbs. of 26% ammonium hydroxide. The goods were thenwashed free from alkali with water.

Bottoming with chrome dyes A dye-bath was prepared by warming the waterin the kettle to 110 F. and adding:

2 oz. of Alizarol Azurine ECA 3 lbs. 8 oz. of Superchrome Blue BC 1 lb.3 oz. of Superchrome Blue B High Conc.

2 lbs. 8 oz. of Superchrome Red E03 3 oz. of Superchrome Yellow RN (C.I. 197) 10 lbs. of calcined Glaubers salt (NELZSOQ 6 lbs. of 56% aceticacid.

The winch was set in motion, and the dyebath was heated'to boilingduring one hour. The bath was boiled for an additional hour and thencooled to 160 F. (by displacing part of the exhausted dyebath with coldwater) at which point 3 lbs. of sodium bichromate, dissolved in water,were introduced. The bath was reheated to boiling during 15 minutes, andboiled for 45 minutes,

after which it-was displaced with water. The goods were rinsed until aclear rinse liquor was obtained. I

Topping ,with indigo A stock vat of indigo was prepared by pasting 10lbs. of indigo NAC 20% Paste (Color Index 117'?) with a solution of 11b. of caustic soda flakes in 5 lbs. of cold water, sprinkling in 1 lb.11 oz. of sodium hydrosulfite powder, and heating the resulting mixtureto 125 F. until reduction of the indigo to the leuco compound wascomplete.

A bath was prepared by adding to the water in the kettle:

6 lbs. of 26% ammonium hydroxide, 2 lbs. of animal glue, and 3 lbs. ofsodium hydrosulfite. The resulting mixture. was heated to 125 F. and thegoods were circulated for 10 minutes. The stock vat of indigo wasquickly added to the bath, and dyeing was carried out at 125 F. for 20minutes. Then 10 lbs. of calcined Glaubers salt (Na2SO4), dissolved in100 lbs. of water, were added slowly during 10 minutes to exhaust thedyebath. The goods were then rinsed and circulated through cold runningwater until the leuco-indigo was oxidized substantially completely.

Thedyed goods thus obtained were scoured with soap in the conventionalmanner to remove loosely-held indigo, rinsed and dried.

The goods were dyed full and well-penetrated navy blue shades possessinggood evenness (levelness) and fastness to cracking.

In the above examples, sodium sulfate is used as an exhausting agentfor' an ammonia-hydrosulfite-glue vat in connection with the dyeing ofchrome-bottomed woolen piece-goods in rope form with indigo, which isclaimed in my application Serial No. 528,711, filed March 20, 1944, now

abandoned. The invention is not limited thereto,

however, 7

Thus, the invention may be applied to the dyeing of wool which has notbeen predyed with another dyestuff; for example, it may be employed inth dyeing of carbonized or uncarbonized wool in an ammoniacal indigovat.

Instead of sodiumsulfate, another neutral alkali-metal sulfate oralkali-metal chloride or a mixture thereof may be employed as-exhaustingagent. The amount of exhausting agent which is required depends upon theconditions employed (e. g., amount of dye liquor, temperature, etc.) andcan be easily determined in each case; for example, by slowly addingvarious amounts of the exhausting agent to the dye liquor, and notingthe minimum amount of exhausting agent which produces dyeings of maximumtinctorial strength (corresponding for all practical purposes withoptimum exhaustion of the dyebath). Thus, in the foregoing example, theuse of substantially less than 10 pounds of sodium sulfate results in anincomplete exhaustion of the dyebath, while the addition ofsubstantially more than 10 pounds of sodium sulfate does not noticeablyimprove the tinctorial strength of the dyeing. In general, at least percent of sodium sulfate, based on the weight of the dye liquor, orequivalent weight of another neutral alkali metal sulfate or an alkalimetal-chloride, is required to effect substantially complete exhaustionof the dyebath.

The dye liquor need not contain glue; but preferably it contains adispersion assistant (such as glue and/or another protective colloid ororganic dispersing agent).

The invention includes the dyeing of proteinous fibers of various kinds,including natural animal fibers (such as wool, silk, hair and the like)and artificial animal fibers (such as those derived from casein, soybeanand the like), all of which are comprehended within the generic termani- J mal fibers herein and in the claims.

Vat Orange R Color Index No. 1217 Vat Red Violet RII Color Index No.1212 Vat Pink FF Am. Assoc. Textile Chemists and Colorists, Vol. XIX(1942), page 523. Brilliant Indigo 4BR. Color Index No. 1184 BrilliantIndigo KMR Color Index No. 1183 I claim:

1. In the dyeing of wool with an indigo by treating the wool with a dyeliquor comprising an indigo in the leuco form, sodium hydrosulfite andammonium hydroxide, the improvement which comprises exhausting the dyeliquor by adding thereto an alkali-metal salt selected from the groupconsisting of the neutral alkali-metal sulfates and the alkali-metalchlorides.

2. In the dyeing of wool with indigo by treating the wool with a dyeliquor comprising indigo in the leuco form, sodium hydrosulfite andammonium hydroxide, the improvement which comprises exhausting the dyeliquor by adding sodium sulfate thereto.

3. In the dyeing of wool with an indigo from anammonia-hydrosulfite-glue vat, the improvement which comprises addingsodium sulfate to the vat in small amounts at a time, while continuingthe dyeing, the total amount of sodium sulfate being at least sufficientto exhaust the vat substantially completely.

4. The method of dyeing wool with indigo which comprisessubjecting woolto a dyeing treatment with a weakly alkaline dye liquor containingleuco-indigo, sodium hydrosulfite, ammonium hydroxide and an organicdispersing assistant, then adding sodium sulfate to the dye liquor, asan exhausting agent, and continuing the dyeing treatment.

5. The method of dyeing wool with indigo which comprises dyeing woolenpiece-goods in a weakly alkaline vat containing leuco-indigo, sodiumhydrosulfite, ammonium hydroxide and glue, and adding sodium sulfate tothe vat in small amounts at a time, as an exhausting agent, whilecontinuing the dyeing, the total amount of sodium sulfate being at leastsufiicient to exhaust the vat substantially completely.

EDWARD WEBER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 972,066 Deinet Oct. 4, 19101,148,966 Hebden Aug. 3, 1915 1,199,273 Iljinsky Sept. 26, 19161,431,136 Villiger Oct. 3, 1922 1,546,969 Clavel July 21, 1925 1,716,720Ellis July 11, 1929 1,819,027 Hood Aug. 18, 1931 FOREIGN PATENTS NumberCountry Date 166,835 Germany Jan. 12, 1906 213,266 Great Britain Jan. 1,1906 340,267 Great Birtain Dec. 19, 1930 419,061 Germany Sept. 19, 1925OTHER REFERENCES Matthews: Application of Dyestuffs, N. Y., 1920,

20 pages 413, 415, 428, 429, 430, 449.

Certificate of Correction Patent N 0. 2,450,773. October 5, 1948.EDWARDQWEBER It is hereby certified that errors appear in the printedspecification of the above numbered patent requiring correction asfollows:

Column 2, line 50, for the words which machine read winch machine column3, lines 68 and 69, strike out Serial N 0. 528,711, filed March 20,1944, now abandoned and insert instead Serial No. 528,771 filed March30, 1944, now Patent No. 2,420,729; column 6, line 14, list ofreferences cited, for Jan. 1, 1906 read Jan. 1, 1925;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Oflice.

Signed and sealed this 5th day of April, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommz'ssianer of Patents.

